1. Field of the Invention
The present invention relates to a floating caliper disc brake used for applying brakes on a vehicle.
2. Related Art
As disc brake assemblies for applying brakes on vehicles, there are floating caliper disc brake assemblies. In the floating caliper disc brake, a caliper is supported relative to a support member in such a manner as to be freely displaced in an axial direction and a cylinder and a piston are provided on only one side of the caliper relative to a rotor.
In the floating caliper type of disc brakes, there are proposed various constructions depending on holding and sliding methods of calipers. In a construction referred to as pin-slide type, a caliper is supported by a guide pin on a support member in such a manner as to be freely displaced. FIGS. 21 to 24 illustrate one of the pin-slide type floating caliper disc brakes that is described in JP-B-58-025894. The pin-slide type floating caliper disc brake is used for motor cycles, and in the disc brake, when the brakes are applied, a caliper 2 is displaced relative to a rotor 1 that rotates together with a wheel (not shown). In such a state that the disc brake is mounted on a vehicle, a support member 3, which is provided in such a manner as to be adjacent to one side to the rotor 1, is fixed to a front fork 43 of a vehicle body via mount holes 4, 4. In addition, the caliper 2 is supported on the support member 3 in such a manner as to be capable of being displaced in an axial direction of the rotor 1.
Due to this, a guide pin 5 and a guide hole 6 are provided in parallel with a center axis of the rotor 1, respectively, in a lug portion 47a that is provided at one end portion (an upper end portion in FIG. 21, and a left end portion in FIG. 22) of the caliper 2 with respect to a rotational direction of the rotor 1 and in an arm portion 49 that is provided at an end portion (the upper end portion in FIG. 21, and the left end-portion in FIG. 22) of the support member 3 with respect to the rotational direction of the rotor 1 as well. Then, the guide pin 5 is inserted in the guide hole 6 in such a manner as to slide freely in the axial direction. A bellows 7 is provided between an outer circumferential surface of a proximal end portion of the guide pin 5 and an opening of the guide hole 6.
In addition, a U-shaped notch is formed in a lug portion 47 provided at the other end portion (a lower end portion in FIG. 21) of the caliper 2, and a distal half portion (a right half portion in FIG. 23) of a rotation preventive or anti-rotation pin 45, which is fixedly provided on the support member 3 in parallel with the center axis of the rotor 1, is disposed inside the notch so formed. Then, both end portions of a wire spring 46, which is provided in such a manner as to straddle an outer circumferential surface of the distal half portion of the anti-rotation pin 45, are locked on internal surfaces of portions situated at both sides of the notch 44 by the lug portion 47b of the caliper 2. In this configuration, the anti-rotation pin 45 is brought into engagement with the notch 44 via the wire spring 46. In addition, in the caliper 2, a cylinder portion 12 and a claw portion 13 are connected to each other via a bridge portion, and a piston 14 is fittingly mounted in the cylinder portion 12 in a fluid-tight fashion so that an inner side (widthwise inward of the vehicle, and a lower side in FIG. 22 and a right side in FIG. 23) pad 10a is pressed against the rotor 1.
When applying the brakes, a pressurized oil is sent into the interior of the cylinder portion 12, so that a lining 15 of the inner side pad 10a is pressed against an internal surface of the rotor 1 from right to left as viewed in FIG. 23. Then, the caliper 2 is displaced downwards as viewed in FIG. 22 and rightwards as viewed in FIG. 23 as a reaction of the pressing force so applied based on the slide of the guide pin 5 and the anti-rotation pin 45 with respect to the guide hole 6 and the wire spring 46, respectively, and the claw portion 13 presses a lining 15 of an outer side (widthwise outer side of the vehicle, and an upper side in FIG. 22 and a left side in FIG. 23) pad 10b against an external surface of the rotor 1. As a result, the rotor 1 is held strongly by the pads on both the internal and external surfaces thereof to thereby apply the brakes.
In the case of the pin-slide type floating caliper disc brake illustrated in FIGS. 21 to 24, since the guide pin 5 is connected to the caliper 2, a through hole 50 needs to be formed (a hole machining process needs to be performed) in the lug portion 47a provided on the caliper 2 so that a guide pin 5 connecting bolt 48 is passed therethrough. In addition, the guide hole 6 needs to be formed (a hole machining process needs to be performed) in the support member 3 so that the guide pin 5 is fitted therein. Furthermore, an anti-rotation pin 45 connecting threaded hole 51 needs to be formed in the support member 3, and the U-shaped notch 44 needs to be formed in the lug portion 47b of the caliper 2 for engagement of the pin 45. Due to this, many pieces of troublesome machining work are involved, and this causes an increase in production costs. Moreover, not only the anti-rotation pin 45 but also the fixing and engagement portions of the anti-rotation pin 45 are provided, and this causes an increase in weight.
Note that JP-Y-61-021620 also discloses a related-art with respect to the present invention.